dildo for 2?

After talking to my gf about size (I'm a high average...not big) I realized she'd want something larger. I decided to take her to a store, and we got 3 dildos (a bit expensive) one big (8x6), another bigger (9x6.5) and a huge thing (12x7). She's got a large vagina on her, and I've wanted to fist her but my knuckles are prohibitively wide. She loves playing with the dildos (not so much the huge one) while I lick her, or even do double play with them. It raised the question: even for a size queen, would that alleviate the need for a biggy? And even, would other girls like that sort of playing, b/c thinking of my past girlfriends, they'd be horrified.